memcpy error prevents sound from gstreamer/libavformat52-based apps

swfdec and gnash both produce this error when loaded as a mozilla plugin. The full error is:

(gtk-gnash:11611): GStreamer-WARNING **: Failed to load plugin '/usr/lib/gstreamer-0.10/libgstffmpeg.so': /usr/lib/libavformat.so.52: R_PPC_REL24 relocation at 0x0cba5a78 for symbol `memcpy' out of range

The outcome is that no flash animations have sound on this machine.

Specs for the host:
OS: Ubuntu Linux 9.04 PPC
kernel: 2.6.28-6-powerpc
package info:
  gstreamer: gstreamer0.10 Version: 0.10.22-1
  libavformat52: 3:0.svn20090303-1ubuntu6
  gnash: 0.8.5-0ubuntu1
  libswfdec-0.8-0: 0.8.4-1
  firefox-3.5: 3.5~b4~hg20090330r24021+nobinonly-0ubuntu1

An animation which triggers the problem can be found just about anywhere -- but my favourite test is at http://www.weebls-stuff.com/wab/pie/ (though youtube works just as well at producing the error -- just takes much longer to load)